[PHOTO] Orion TV and Video Sales, 1265 Davenport Road

Located at the foot of the Glenholme steps I blogged about this weekend past, the art-deco font of the signage for Orion TV and Video Sales at 1265 Davenport Road caught my eye. To me, the whole street evoked the 1980s, perhaps for reasons having to do with the cast of light on that Sunday afternoon in November; the anachronistic font confirmed the matter for me.

[BRIEF NOTE] On Kappa Andromedae b

News that an exoplanet has been discovered orbiting the star Kappa Andromedae, a relatively massive and bright star some 170 light years away, stands out because of the method of Kappa Andromedae b's discovery: it was directly imaged.



The basic elements of this discovery were described by Universe Today's Nancy Atkinson.

Kappa Andromedae (k And) is a very young star, with an estimated age of 30 million years (in comparison our Sun is around 5 billion years old). The planet, called k And b (“Kappa Andromedae b), is about 10% larger than Jupiter, but it is a heavy world — it has a mass of about 13 times that of Jupiter.

This means that it could very well be either a planet or a very lightweight brown dwarf, an object that is intermediate between planets and stars. However, the astronomers are leaning towards the circumstantial evidence which indicates that it is likely to be a planet.

Since stars are much brighter than their planets –typically by a factor of a billion or more – exoplanets are usually lost in the star’s glare when using traditional observational techniques. The Subaru team used a different technique called angular differential imaging, which combines a time-series of individual images in a manner that allows for the otherwise overwhelming glare of the host star to be removed.

In the infrared image, above, the tiny point of light that is the planet Kappa And b. Since the planet orbits the star at some distance, the SEEDS observing team was able to distinguish the object’s faint light by effectively covering up the light of the star.

The large mass of both the host star and gas giant provide a sharp contrast with our own solar system. Observers and theorists have argued recently that large stars like Kappa Andromedae are likely to have large planets, perhaps following a simple scaled-up model of our own solar system. But experts predict that there is a limit to such extrapolations; if a star is too massive, its powerful radiation may disrupt the normal planet formation process that would otherwise occur. The discovery of the super-Jupiter around Kappa Andromedae demonstrates that stars as large as 2.5 solar masses are still fully capable of producing planets within their primordial circumstellar disks. This is key information for researchers working on models of planet formation.

Bad Astronomy's Phil Plait reacted to the interesting question of whether Kappa Andromedae b is actually a planet or a brown dwarf.

The planet κ And b pops right out in the Subaru telescope picture, which is pretty amazing; typically a star is a billion times brighter than any planets orbiting it, so being able to see the planet so clearly is very nice. It helps that the planet orbits the star over 8 billion kilometers (5 billion miles) out, reducing the glare significantly. It also promises that more observations in the future will reveal a lot more information about it.

The current analysis indicates the planet is about 13 times the mass of Jupiter, and that made me raise my eyebrows. We don’t really have a good definition of what a “planet” is, but a star is something so massive it can fuse hydrogen into helium in its core—the pressure and temperature are so high in the star’s heart that it acts something like a controlled thermonuclear bomb.

But there exists a type of object called a brown dwarf that is midway between a planet and a star. It’s massive enough that for a time in its core it can fuse a particular flavor of hydrogen called deuterium, but after a while that turns off. Anything below that mass doesn’t have the oomph to get fusion started, and we call those objects planets. The upper mass limit before deuterium fusion starts? Thirteen times that of Jupiter, right where κ And b is.

So it’s possible that, by strict definition, κ And b isn’t a planet. However, the mass estimate for it depends on a lot of things: the age of the system, how bright it is, its temperature, what colors it has (literally, comparing how much light it gives off in the blue end of the spectrum versus red, and so on; that can tell an astronomer a lot about the object). These numbers are fed into computer models that then calculate the mass.

The age is most important, because while an old planet (like Earth) shines by reflecting light from its star, a young planet is still hot from its formation, and glows on its own, fading with time. It’s like a hot coal that shines white, then fades and turns redder with time. The more massive a young planet is, the brighter (and bluer) it is. For κ And b, one model gives a mass of 13 Jupiters, another gives it a lower mass of closer to 12. If the latter is correct, we have a true planet on our hands. Even if it’s more massive than that, other factors can come into play keeping it a planet by definition.

But either way this is pretty cool. For one thing, it tests our models to their limits, which is always good. We want better models! Finding test cases near the limits is a good way to figure out how to refine our understanding of the physics. And honestly, our definitions are a little arbitrary anyway. Don’t let some hard-and-fast interpretation keep you away from the sheer wonder of this discovery!

The discovery paper is online at arXiv, "Direct Imaging Discovery of a `Super-Jupiter' Around the late B-Type Star Kappa And".

[LINK] "Russia and Europe joint Mars bid agreement approved"

The European Space Agency seems to be rapidly expanding its capacities. Not only has it built a global tracking network comparable to NASA's, but the collaboration with Roscosmos that has led to last year's agreement to launch an ESA probe to Jupiter on a Russia rocket has extended to plans to enlist Roscosmos to replace NASA in the ESA's ExoMars probe. The BBC's Jonathan Amos reports.

European Space Agency member states have approved the agreement that would see Russia take significant roles in Red Planet missions in 2016 and 2018.

The former is a satellite that will look for methane and other trace gases in the atmosphere; the latter will be a surface rover.

Russian participation fills a void left by the Americans who pulled back from the projects earlier this year.

For a while, it looked as though the ventures, known as ExoMars, might have to be cancelled. But Russian desire to pick up many of the elements dropped by the US means ExoMars is now on a much surer footing.

Esa member states indicated their happiness with the cooperation text on Monday. All that remains is for the documentation to be signed by both parties.

[. . .]

The planned agreement calls for Russia to provide the Proton rockets to send the two ExoMars missions on their way.

Russia would also get instrument space on the 2016 satellite and the 2018 rover. In addition, its researchers would join the science teams that exploit the missions' data.

One key contribution would be the landing system that places the rover on the surface of the Red Planet. With the exception of some key components, this would be built by Russian industry.

[ISL] "After Saving Fire Island, Line of Defense Is Lost to the Sea"

The New York Times' Lisa Foderaro reports that Fire Island, a barrier island off of the Atlantic coast of Long Island that's famous as a tourist destination (particularly for GLBTQ tourists), is threatened. In the aftermath of Hurricane Sandy, the dunes that protected built-up areas of the islands have been washed away.

Initial reports of the storm’s impact on Fire Island were dire. And while it did breach the 32-mile island in two places, flood many of the 17 communities — during the storm, the bay and the ocean met, subsuming much of the island under feet of water — and ruin dozens of oceanfront houses, the verdict now is that it could have been far worse.

Unlike many of the hardest-hit areas, Fire Island had a robust system of dunes, ranging from 10 to 20 feet in height, that largely absorbed the ocean’s wrath, saving the bulk of the island’s 4,500 homes. The dunes were replenished only a few years ago, after many residents agreed to accept a new tax to help finance the work. Now the dunes are gone.

“The dunes served their purpose,” said Steven Jaffe, president of the Ocean Bay Park Association, one of the homeowner groups on the island. “But they were decimated, and now we have a winter coming and we don’t know what will happen.”

Fearful of facing the next big storm without the protection of the dunes, some community associations are already reviving them, filling government-sanctioned bags, known as Geocubes, with sand, and building a tight wall where the dunes once stood. They are also scooping up the mounds of sand that washed onto walkways — the island is known for its paths and red wagons where others have roads and cars — and returning it to the dunes.

But it will take the Army Corps of Engineers and federal money, residents say, to bring them all the way back to where they were.

As they follow the debate that has erupted over the wisdom of rebuilding on storm-lashed beaches, community leaders are making the case that Fire Island is critical to Long Island’s welfare. They cite one study suggesting that the island, with only a few thousand homes, and 200 year-round families, protects a stretch of the mainland with 13,000 homes and properties, valued at roughly $10 billion.

“We’re the first line of defense for Long Island, and the dunes are our first line of defense,” said Suzy Goldhirsch, president of the Fire Island Association, an umbrella group of community associations. “We’re self-reliant. We’re island people. But we need support.

[LINK] "Greenland's viking settlers gorged on seals"

Via Will Baird at The Dragon's Tales comes a report from a Danish-Canadian team suggesting that the Norse settlers of medieval Greenland actually had a much more diverse diet, drawing heavily on local seals, than previously assumed. This fleibility in dietary matters, greater than expected, hints at a less catastrophic end to Greenlandic Norse society than expected--no sudden breakage or collapse, instead a story of rudimentary adaptation to the environment coupled with a quiet enough decline.

"Our analysis shows that the Norse in Greenland ate lots of food from the sea, especially seals," says Jan Heinemeier, Institute of Physics and Astronomy, Aarhus University.

"Even though the Norse are traditionally thought of as farmers, they adapted quickly to the Arctic environment and the unique hunting opportunities. During the period they were in Greenland, the Norse ate gradually more seals. By the 14th century, seals made up between 50 and 80 per cent of their diet."

The Danish and Canadian researchers are studying the 80 Norse skeletons kept at the University of Copenhagen's Laboratory of Biological Anthropology in order to determine their dietary habits. From studying the ratio of the isotopes carbon-13 and carbon-15, the researchers determined that a large proportion of the Greenlandic Norse diet came from the sea, particularly from seals. Heinemeier measured the levels of carbon isotopes in the skeletons, Erle Nelson of Simon Fraser University, in Vancouver, Canada, analysed the isotopes, while Niels Lynnerup of the University of Copenhagen, examined the skeletons.

"Nothing suggests that the Norse disappeared as a result of a natural disaster. If anything they might have become bored with eating seals out on the edge of the world. The skeletal evidence shows signs that they slowly left Greenland. For example, young women are underrepresented in the graves in the period toward the end of the Norse settlement. This indicates that the young in particular were leaving Greenland, and when the numbers of fertile women drops, the population cannot support itself," Lynnerup explains.

The findings challenge the prevailing view of the Norse as farmers that would have stubbornly stuck to agriculture until they lost the battle with Greenland's environment. These new results shake-up the traditional view of the Norse as farmers and have given archaeologists reason to rethink those theories.

"The Norse thought of themselves as farmers that cultivated the land and kept animals. But the archaeological evidence shows that they kept fewer and fewer animals, such as goats and sheep. So the farming identity was actually more a mental self-image, held in place by an over-class that maintained power through agriculture and land ownership, than it was a reality for ordinary people that were hardly picky eaters," Jette Arneborg, archaeologist and curator at the National Museum of Denmark, says.